Golden Ratio Flashlight - CNC Lathe Class

The Challenge: Using the principles of dynamic symmetry, design a flashlight to be economically mass-produced by students in an introductory CNC lathe class.

Technical Approach: Dynamic symmetry and the golden ratio are graphical tools which help develop proportionality and coincidences within a design. The creation of the flashlight's visual appearance was my first attempt at applying the powerful principles of dynamic symmetry to a three dimensional object. Over the course of 18 hand-drawn iterations, my design evolved as I tried various ratios and became more comfortable with the system. The finished profile was then merged with a minimalist mechanical design and undertaken as a manufacturing project by my January-term CNC lathe class at the MIT Hobby Shop.

Selected Design Features: The profile of the flashlight is based on a system of four adjacent phi rectangles. These were used to establish proportionality between the head and handle diameter and the length of each reticulated segment. Additionally, this system was useful in placing the vertices of the conical sections at visually important locations. From a mechanical standpoint, the flashlight consists of two aluminum parts and several waterjet-cut wafers. The handle houses a single battery who's positive terminal is brought into contact with an LED by tightening the handle into the head. A set of plastic and metal wafers route the cathode of the LED to the negative terminal of the battery through the aluminum handle. In an effort to reduce the number of parts, a parabolic dish is machined directly in the aluminum head, and is protected by a press-fit lexan shield. The manufacture of this project was ideal for a class because of the necessity of multiple fixtures and cutting tools.